I've never seen a scan line on my 3000 so they aren't really noticeable. Also the gen firmware for 3000 is getting an update around Halloween to allow it to play newer games.

To brick the 3000 you would have to mess with the flash. Doesn't happen during playing isos/cso and psn eboots and psx eboots.
If it is bricked you have to send it to sony and when you get it back most likely it won't be hackable.
Yes you can restore the 2000.

I'd say psp 3000 just because of the screen quality(I have one with cfw). However if you don't want the hassle of restarting cfw everytime you turn off your psp then go for the 2000. Since it will be able to be restored you don't have to worry about bricking it.

they,re both pretty much the same but i would go with the 2000 because it will have more features for homebrew and games and you will be able to use the good firmwares like 5.50gen-D or 5.00m33-6 if you want

As much as I LOVE my PSP 3000 (the screen really does make a difference), as far as hacking/etc. goes, the PSP 2000 is just infinitely more reliable. The fact that the CFW is higher makes certain games play without glitches (PSN Metal Gear Solid, for one).

PSP 3000, if bricked, is then a paperweight- I haven't seen anything about unbricking PSP 3000's, but maybe someone else knows more about that, and will reply. Bricking could happen just by a simple mistake when installing CFW (trying to write to the flash or something, instead of properly following directions)- it happened to the pspslimhacks.com people! PSP 2000's, with the right motherboard (you're Sure of what motherboard it has, right?) can be unbricked, use Pandora battery, Not use Pandora battery, etc.

Maybe someone will find an exploit for the official 5.50 FW (or higher) for PSP 3000's, or something to have 'permanent' CFW, but right now, That is unknown. If there was some kind of PSP 3000 screen mod for the 2000, I wouldn't even hesitate about saying, "Get the 2000".

I'm a little worried about bricking the PSP-3000. How could that happen?
If you fool arround with the flashes or install homebrew \ plugins \ anything that touches the flashes you could brick the PSP.

If I brick the PSP-2000, I can restore it with the Pandora Battery/Magic Memory Stick, right?
Yes indeed you can. (If you are 100% sure your PSP 200x is fully hackable)

What can I do on the PSP-2000, that I can't do on the PSP-3000?
Boot into CFW without fooling arround with Chickhen.
Other than that you have to be a less carefull with it when you have a pandora set at hand when installing homebrew ect.
And not to forget timemachine which can not be ran on a 300x.

Note: You must be 100% sure your 200x is fully hackable.
Some 200x models have a newwer motherboard which prevents you from installing full CFW to it.

Also I would go for the 200x one seeing the fact it will take quite some time untill the 300x is fully hacked.
And by the time it does you can prob get one cheap at the store somewhere. (As the PSPGo is out now)

What can I do on the PSP-2000, that I can't do on the PSP-3000?
I'm only gonna answer this question because all the others have pretty much been answered as much as they can. As people have mentioned you have to load custom firmware every time on the 3000 and have 5.03. This means you are doomed to forever stay on 5.03 until another exploit. This means that eventually newer games may begin to not work and you will lose any features Sony ever adds to newer firmwares.

Some 200x models have a newwer motherboard which prevents you from installing full CFW to it.
Make sure you don't forget what Vistabuser said because newer model 2000's are almost equivalent to buying a 3000 (doomed to forever live on 5.03).